Ion exchange type liquid treatment apparatus commonly utilize liquid distributors to provide more uniform flows of the liquid to be treated and of the regenerating and rinse fluids through the bed of exchange material in the tank. It is desirable in such treatment apparatus to locate the lower distributor closely adjacent the bottom of the treatment tank in order to minimize the volume of the exchange resin below the distributor that is not fully contacted by the liquid to be treated or by the regeneration and rinse fluids. However, such treatment tanks are commonly formed with a dished bottom wall and this complicates the problem of locating the distributor assembly closely adjacent the bottom.
It has heretofore been proposed, for example as shown in U.S. Pat. No. 2,364,775, to bend or otherwise form the several generally radial distributor conduits with a longitudinal curve to more clearly conform to the curvature of the bottom. However, this necessitates separate bending or forming of each of the distributor conduits and markedly increases the overall cost of making the distributor. Moreover, the curvature of the bottom walls is different for tanks of different size and this would require forming distributor conduits with different curvature. Further, longitudinally curved distributor conduits cannot be turned about their axes to thread the distributor conduits in the header when the distributor is mounted closely adjacent the tank bottom and, when longitudinally curved distributor conduits are used, it is either necessary to provide a special header which allows installation and removal of the curved distributor conduits without turning of the conduits, for example as shown in the aforesaid U.S. Pat. No. 2,364,775, or to raise or even remove the entire distributor from the tank to provide clearance for turning the curved conduits.
It is an object of the present invention to overcome the disadvantages of the prior art by providing a liquid treatment apparatus having an improved distributor construction which can be generally conformed to the dished bottom in a treatment tank to extend closely adjacent thereto and which utilizes straight pipe sections and standard pipe fittings.
Another object of this invention is to provide an improved distributor construction and suport therefor which supports the distributor on the dished bottom of the treatment tank in closely spaced relation thereto.
Still another object of the invention is to provide a distributor for a treatment tank in which the various components used in making the distributor can be easily assembled inside the tank.
Accordingly, the present invention provides a liquid treatment apparatus, including a tank having an upwardly dished bottom wall, a lower liquid distributor having a header mounted centrally in opening in the bottom wall and distributor conduits connected to the header and extending outwardly therefrom at angularly spaced locations around the header and wherein the distributor conduits each include a first straight conduit section extending generally radially outwardly from the header and a second straight conduit section connected to the outer end of the first conduit section by a pipe elbow, the pipe elbow on each distributor conduit extending oblique to the longitudinal plane defined by the respective first conduit section and the tank axis and such that each second conduit section extends at an acute angle to the longitudinal plane through the respective first pipe section and also at an acute angle to a plane perpendicular to the tank axis to provide a liquid distributor having a shallow upwardly dished configuration that generally conforms to the dished configuration of the bottom wall of the tank.
The invention also advantageously provides an improved distributor support including radially extending arms that are supported on the dished bottom wall of the tank to extend at a shallow angle thereto and with ring members interconnecting the arms for supporting the distributor conduits.